When deploying wireless communications systems such as, for example, cellular systems, in indoor environments in general, traditional kinds of antennas can be difficult to use. In such environments, use is sometimes instead made of so called “leaky cables”, also sometimes referred to as leaky feeders or radiating cables.
A leaky cable is, as the name implies, a cable which is capable of conducting electrical energy, and which has been provided with apertures in order to make the cable radiate, i.e. to allow some of the energy to “leak” from the cable, thus enabling the cable act as an antenna. Such an antenna, i.e. a leaky cable, will be able to act as both a receiving and a transmitting antenna. Due to its nature of a cable, a “leaky cable antenna” will, as compared to a traditional antenna, act more like a line source than a point source, thus making it easier to obtain coverage in tunnels or where a high degree of “shadowing” occurs when using a point source antenna. An example of the latter is an indoor scenario, e.g. an office landscape.
U.S. Pat. No. 4,091,367 and U.S. Pat. No. 5,247,270 disclose leaky cable systems which are intended for use as intruder detection systems, with the disclosure of the latter document being particularly intended for burial below ground or for use in mines.